acorn cnc controller rev4 specifications manual · direction 1 input 3 step 4 step 3 step 2 step 1...

ACORN CNC controller _rev4 Specifications ManualFor Revision 190201Updated 2/22/19

Overview

ACORN is technically a breakout board for the BeagleBone Green or BeagleBone Black embedded computer. The remainder of this document will refer to the breakout board with BeagleBone installed as ACORN. It is a low cost motion control processor, PLC, and drive interface board. It is intended to operate entry level machining equipment with up to four axes.

Features

Function:Motion Control Processor, PLC, and Drive

InterfaceMaximum number of Axes: 4Maximum pulse rate: 400kHzControl Interface: 100 Mb/s Ethernet to PCDrive Application: Drives with step and direction inputsDigital PLC Inputs: 8Digital PLC Outputs: 8Analog Output resolution: 12 bitsDimensions (W*D*H): 5.4 * 4.2 * 0.7 inches

svn://192.168.0.222/hardware/ACORN/160520/docs/ACORN_MAN.doc MRR of 10

Typical Connections

Connections

Two connection methods are available. A female DB25 connector is available that can mate with many stepper control units with a straight through cable. The inputs and outputs are 5V compatible. Check the DB25 pinout and circuit descriptions to determine if it is compatible with a particular control unit. The DB25 provides the simplest and quickest connection method if it is compatible.

Screw terminals are available for custom configurations. This allows for additional I/O and the most connection versatility. All input and output signals on the DB25 connector are also available on the screw terminals with up to 24V levels.

Inputs may only be used on the DB25 or screw terminal, not both. For example, only screw terminal input 1 or DB25 input 1 may be connected at the same time. However, screw terminal input 1 may be used at the same time as DB25 input 2.


DB25 (H6) Signals

Direct ion 3

Chassis GND

Direct ion 4

5

9

4

8

3

7

2

6

1

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

Direct ion 2

Direct ion 1

Input 3

Step 4

Step 3

Step 2

Step 1

Output 4

Output 3

Input 4

Output 2Output 1

Input 2

Input 1

Input 5

COM

Drive Interface Section

Four sets of step and direction outputs are provided to control motor drives. The outputs can provide up to 400kHz step frequency. Screw terminal (open collector) or DB25 (5V push / pull logic) connection must be selected based on the voltage level and input circuit of the motor drive. Most industrial class drives will use 24V optically isolated inputs similar to the first example below. Hobby class drives will often use low current 5V isolated inputs or logic inputs similar to the second example.

External Power Supply

+24 VDC

COM

H2 or H3

3

External Power Supply May Be 5to 24V Depending on Application

DR

4

ST

ACORN Screw Terminal Outputs

EN

2

Direction

Motor Drive Connection Example

COM

Stepper Drive

1Enable

Step

24 COM

Simplified View


Simplified View

DR

H6

18

+5 VDC

COM

2 ST

Stepper Drive

+5 VDC

Direction

14

15

16

17

18

19

20

22

23

24

2512

3

13

7

2

6

5

1

9

10

4

11

821

+5 VDC

COM

3

COM

ACORN DB25 Outputs

+5 VDC

Motor Drive Connection Example

Step

PLC Section

The ACORN has 8 digital inputs, 8 digital outputs, and one analog output. Check the “ACORNI/O Map” and “ACORN Specifications” sections to determine I/O type and capability.

Outputs

5V logic level relay outputs are available on the DB25 connector. 8 open collector outputs are normally wired with a ribbon cable to an external 8 relay board.

+5 VDC

OUT P UT

Internal Circuitry

DB25 Connector Outputs

+24 VDC

Common

Output

Screw Terminal Outputs

Internal Circuitry


Inputs

ACORN uses optically isolated inputs for screw terminal inputs. These inputs can be used with 24 VDC sensors or switches. The 24 VDC for inputs may be supplied from the ACORN logic supply. For improved isolation and noise immunity, a separate 24 VDC may be used to power the inputs. Compare the specifications of sensors to the “ACORN Specifications” chart to ensure reliable operation.

DB25 inputs are only compatible with 5V logic levels. These inputs are not isolated.

INP UT

DB25 Connector Inputs

+5 VDC

Internal Circuitry

INP UT

+24 VDC

Screw Terminal Inputs

220

Internal Circuitry

1.2k


Input Connection Examples

4

ACORN Inputs

5

+24 VDC

Switch Wiring Example

24 COM


2

H1 or H4

1

3

3

ACORN Inputs

H1 or H4

Sensor

Sinking (NPN) Sensor Wiring Example

+24 VDC

5


+24 VDC

24 COM

24 COM

Notice: Do not use 2 wire sensors. The voltage drop across 2wire sensors usually causes unreliable operation. If a 2 wiresensor works when connected, it still may be unreliable for longterm use.

1

4

2


Analog Output

An analog output is provided for controlling spindle speed. The output voltage range is 0 to 10 VDC.

-

+

Analog Output

Analog Comm on

Analog Output

+24 VDC ANALOG

Internal Circuitry

24 COM

Analog Output Calculations

The analog output uses a 12 bit digital to analog converter (DAC) to generate analog from the DAC request sent from the PLC program. The 12 bit value allows a DAC request of 0 to 4095, which corresponds to 0 to 9.998 volts in the 0 to 10V range.

Analog Output Wiring

The analog output should be wired using a shielded twisted pair for best results. The analog output terminal is paired with a common terminal for direct wiring of the signal, common, and shield. In most cases, it is best to connect the shield to the common only at the ACORN. Routing analog cables away from power wires and other noise sources is also critical for good performance. See “ACORN Connections” section for terminal locations.


ACORN I/O Map

Input Specification Input Location 1 Input Location 2

Number Function Type Connector Pin Type Connector Pin

1 General Purpose Sourcing H4 5 Logic w/ 5V Pullup H6 10




5 General Purpose Sourcing H1 5 Logic w/ 5V Pullup H6 156 General Purpose Sourcing H1 4 - - -7 General Purpose Sourcing H1 3 - - -8 General Purpose Sourcing H1 2 - - -

Output Specification Output Location 1 Output Location 2Number Function Type Connector Pin Type Connector Pin

1 General Purpose Open Collector H10 2 5V Logic H6 12 General Purpose Open Collector H10 3 5V Logic H6 14

3 General Purpose Open Collector H10 4 5V Logic H6 164 General Purpose Open Collector H10 5 5V Logic H6 17

5 General Purpose Open Collector H10 6 - - -6 General Purpose Open Collector H10 7 - - -7 General Purpose Open Collector H10 8 - - -8 General Purpose Open Collector H10 9 - - -

17-28 Analog out 12 bit DAC H8 1 - - -

ACORN Specifications

Characteristic Min. Typ. Max. Unit24 Volt Supply Current (Vsupply) 0.5 - - A24V Input Pullup Voltage (Vinp) 22 - 26 VDC24V Input Off Voltage 19.1 - 26 VDC24V Input On Voltage 0 - 5.9 VDC24V Input Operating current 9 11 15 mAOpen Collector Output Current 0 10 50 mAOpen Collector Output Voltage 0 24 26 VDCDB25 Input Pullup Voltage (internal) (VCC) 4.35 4.75 5.15 VDCDB25 Input On Voltage VCC x 0.7 - - VDCDB25 Input Off Voltage - - VCC x 0.3 VDCDB25 Output High Voltage 3.61 4.7 VCC VDCDB25 Output Low Voltage 0 0.1 0.44 VDCDB25 Low Level Output Current 0 3 20 mADB25 High Level Output Current 0 3 20 mAAnalog Output Current 0 1 10 mAAnalog Output Voltage 0 - 10 VAnalog Output Resolution - 12 - bits

Relay Output Current (relay board) 0.01 - 10 A @ 125VACRelay Output Current (relay board) 0.01 - 10 A @ 28VDC5 Volt Supply Current (relay board) 0.3 - - A

Size: 5.4 * 4.2 * 0.7 (W*D*H) Inches


ACORN Connections

Ena

ble

2

In 4

Enc

oder

Inp

ut

Ena

ble

3

Common

N/C

CommonE

nabl

e 1

OUT1

Out 6

Output 4

+Index

Direction 4

Ste

p 1

Common

Heartbeat (RED)

Inpu

t 5

Common

+A

Input 1

Ste

p 2

OUT4

In 3In

put 6

Input 5

+B

Output 1

Dir

ecti

on 1

Ena

ble

1

H4In

put 2

4 V

DC

Common

In 1

Input 3

Com

mon

In 7

H1

Inpu

t 8

Input 2

Out 7

Step4

Dir

ecti

on 2

In 6

H2

Inpu

t 7

Ena

ble

2

Input 4

In 2

Step 1C

omm

on

In 8

H3

Com

mon

Output 3

+24 Power (GRN)

Common

Eth

erne

t

In 5

Out 8

Ste

p 4

OUT8

Input 24 VDC

Out 2

Step 2

24 V

DC

Out 3

Ena

ble

4

OUT7

Input 2 Out 1

Step3

24 V

DC

H9

Dir

ecti

on 4

OUT6

Input 1

H10Direction 1

+5VC

omm

on

H8

Ena

ble

3

OUT5

Input 4

Ena

ble

4

Output 2

Return

Com

mon

P10

Ste

p 3

5V

Input 3

Direction 3

-A

Cha

ssis

GN

D

H6

Dir

ecti

on 3

OUT3

Ana

log

Com

mon

Out 4

Common

-Index

Common

Com

mon

OUT2

Ana

log

0 -

10V

Out 5

Common

-B

Direction 2


ACORN Mounting Footprint

(137.2mm)5.400"

(121.9mm)

(106.7mm)

4.800"

4.200"

(91.4mm)3.600"


Acorn CNC control board Mounting Footprint.

- Holes are clearence for 6-32 (.1495” diameter)- 6-32 stando�s are recommended

4.8”

5.4”

4.2”3.6”

acorn cnc controller rev4 specifications manual · direction 1 input 3 step 4 step 3 step 2 step 1...

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